Battery separators with cross ribs and related methods
View Patent ↗A separator for a lead acid battery is a porous membrane having a positive electrode face and a negative electrode face. A plurality of longitudinally extending ribs, a plurality of protrusions or a nonwoven material may be disposed upon the positive electrode face. A plurality of transversely extending ribs are disposed upon the negative electrode face. The transverse ribs disposed upon the negative electrode face are preferably juxtaposed to a negative electrode of the lead acid battery, when the separator is placed within that battery.
1. A separator for a lead acid battery comprising:
a porous membrane having a positive electrode face and a negative electrode face;
a plurality of longitudinal ribs extending in a machine direction disposed upon said positive electrode face; and
a plurality of transverse ribs extending in a cross-machine direction disposed upon said negative electrode face, said transverse ribs adapted to be juxtaposed to a negative electrode, being linear, or cross-hatched, or sinusoidal, or combinations thereof.
2. The separator of claim 1 wherein the transverse ribs are shorter and more closely spaced than the longitudinal ribs.
3. The separator of claim 1 wherein the transverse ribs and the longitudinal ribs are formed by calender roll molding.
4. The separator of claim 1 wherein the separator is one of a macroporous membrane and a microporous membrane.
5. The separator of claim 4 wherein the separator is a polyethylene microporous membrane.
6. In a separator for a flooded automotive lead acid battery having a porous backweb with a first surface and a second surface, the improvement comprising: a plurality of transverse ribs being disposed upon the second surface of the backweb and extending in a cross-machine direction, wherein the transverse ribs are linear, or cross-hatched, or sinusoidal, or combinations thereof.
7. The separator of claim 6 wherein the first surface is a positive electrode face and the second surface is a negative electrode face;
at least one of no ribs, a plurality of longitudinally extending ribs, a plurality of projections, and a nonwoven material being disposed upon said positive electrode face;
and wherein said transverse ribs disposed upon said negative electrode face being adapted to be juxtaposed to a negative electrode, when the separator is placed within the lead acid battery.
8. The separator of claim 6 wherein the separator is one of macroporous and microporous.
9. A lead acid battery comprising: a housing containing a positive electrode spaced apart from a negative electrode with a porous separator located between said positive electrode and said negative electrode and a liquid electrolyte in ionic communication between said positive electrode and said negative electrode, said separator having a plurality of longitudinal-ribs extending in a machine direction and disposed on a first surface of said separator and a plurality of transverse ribs extending in a cross-machine direction and disposed upon a second surface of said separator, said plurality of longitudinal ribs being juxtaposed to said positive electrode and said transverse-ribs being juxtaposed to said negative electrode, wherein the transverse-ribs are linear, or cross-hatched, or sinusoidal, or combinations thereof.
10. The battery of claim 9 wherein the transverse-ribs are shorter and more closely spaced than the longitudinal-ribs.
11. A method of making a separator for a flooded automotive lead acid battery, the separator having a porous backweb with a first surface and a second surface, the method comprising the step of: forming a plurality of transverse ribs on the second surface of the backweb extending in a cross-machine direction, the transverse ribs are linear, or cross-hatched, or combinations thereof.
12. The method of claim 11 wherein the first surface is a positive electrode face and the second surface is a negative electrode face, and further comprising the steps of:
forming a plurality of longitudinally ribs on said positive electrode face.
13. The method of claim 11 wherein the first surface is a positive electrode face and the second surface is a negative electrode face, said negative electrode face being adapted to be juxtaposed to a negative electrode when the separator is placed within a lead acid battery, and further comprising the steps of:
forming a plurality of longitudinally extending fissures, channels, recesses, or openings in said transverse ribs disposed upon said negative electrode face.
14. The battery separator of claim 1 wherein the separator comprises ultrahigh molecular weight polyethylene and silica or has a bending stiffness of at least 20 mN.
15. The battery separator of claim 6 wherein the separator comprises ultrahigh molecular weight polyethylene and silica or has a bending stiffness of at least 20 mN.
16. The battery of claim 9 wherein the separator comprises ultrahigh molecular weight polyethylene and silica or has a bending stiffness of at least 20 mN.
17. The separator of claim 1 wherein the transversely extending ribs are formed integrally from the porous membrane, or are discontinuous or include a longitudinally extending fissures, channels, recesses, or openings.
18. The separator of claim 6 wherein the transversely extending ribs are formed integrally from the porous membrane, or are discontinuous or include a longitudinally extending fissures, channels, recesses, or openings.
19. The battery of claim 9 wherein the transversely extending ribs are formed integrally from the porous membrane, or are discontinuous or include a longitudinally extending fissures, channels, recesses, or openings.
20. The method of claim 11 wherein the separator comprises ultrahigh molecular weight polyethylene and silica or has a bending stiffness of at least 20 mN.
21. The method of claim 11 wherein the transversely extending ribs are formed integrally from the porous membrane, or are discontinuous or include a longitudinally extending fissures, channels, recesses, or openings.